Goudarzi Afsaneh, Amiri-Yekta Amir
Department of Clinical Biochemistry, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran. Electronic Address:
CNRS UMR 5309; INSERM, U1209; Université Grenoble Alpes; Institute for Advanced Biosciences, 38700 Grenoble, France.
Cell J. 2020 Apr;22(1):66-70. doi: 10.22074/cellj.2020.6306. Epub 2019 Sep 8.
Acyl-CoA synthetase short-chain family member 2 (ACSS2) activity provides a major source of acetyl-CoA to drive histone acetylation. This study aimed to unravel the ACSS2 expression during mouse spermatogenesis, where a dynamic and stage-specific genome-wide histone hyperacetylation occurs before histone eviction.
In this experimental study, ACSS2 expression levels during spermatogenesis were verified by Immunodetection. Testis paraffin-embedded sections were used for IHC staining with anti-H4 pan ac and anti-ACSS2. Co-detection of ACSS2 and H4K5ac was performed on testis tubular sections by immunofluorescence. Proteins extracts from fractionated male germ cells were subjected to western-blotting and immunoblot was probed with anti- ACSS2 and anti-actin.
The resulting data showed that the commitment of progenitor cells into meiotic divisions leads to a robust accumulation of ACSS2 in the cell nucleus, especially in pachytene spermatocytes (P). However, ACSS2 protein drastically declines during post-meiotic stages, when a genome-wide histone hyperacetylation is known to occur.
The results of this study are in agreement with the idea that the major function of ACSS2 is to recycle acetate generated after histone deacetylation to regenerate acetyl-CoA which is required to maintain the steady state of histone acetylation. Thus, it is suggested that in spermatogenic cells, nuclear activity of ACSS2 maintains the acetate recycling until histone hyperacetylation, but disappears before the acetylation-dependent histone degradation.
酰基辅酶A合成酶短链家族成员2（ACSS2）的活性为驱动组蛋白乙酰化提供了主要的乙酰辅酶A来源。本研究旨在揭示小鼠精子发生过程中ACSS2的表达情况，在此过程中，全基因组范围的组蛋白高度乙酰化在组蛋白去除之前动态且阶段特异性地发生。
在本实验研究中，通过免疫检测验证精子发生过程中ACSS2的表达水平。睾丸石蜡包埋切片用于抗H4泛乙酰化和抗ACSS2的免疫组化染色。通过免疫荧光在睾丸管状切片上对ACSS2和H4K5ac进行共检测。从分离的雄性生殖细胞中提取的蛋白质进行蛋白质印迹分析，并用抗ACSS2和抗肌动蛋白抗体检测免疫印迹。
所得数据表明，祖细胞进入减数分裂会导致ACSS2在细胞核中大量积累，尤其是在粗线期精母细胞（P）中。然而，在减数分裂后阶段，当已知全基因组范围的组蛋白高度乙酰化发生时，ACSS2蛋白急剧下降。
本研究结果与以下观点一致，即ACSS2的主要功能是回收组蛋白去乙酰化后产生的乙酸以再生维持组蛋白乙酰化稳态所需的乙酰辅酶A。因此，提示在生精细胞中，ACSS2的核活性维持乙酸循环直至组蛋白高度乙酰化，但在依赖乙酰化的组蛋白降解之前消失。
